"At the Fourth of July, we sort of expect it and anticipate it," he told The Times. "It's leading up to the Fourth of July, when people are setting off their M-80s and you don't expect it. I would catch myself jumping all the time because it brings me back to the night we were attacked and reminds me of when they shot mortars into our compound."

Becerra, who lives in the Indiana Harbor neighborhood of East Chicago, started his career in the Marine Corps Reserves and served in Desert Storm at age 20.

Now he is in the Army National Guard and twice was deployed to Afghanistan as a member of the Valparaiso-based engineer unit that experienced six soldier deaths in 2012.

"We come back changed. We come back different," he said.

As a mechanic, Becerra repaired trucks that were damaged by improvised explosive devices and gunfire. He was in denial until recently about the mental impact serving overseas had.

"There are times when you least expect it, and you'll get startled, and it'll bring something back," Becerra said.

The smells in a certain part of Gary remind him of Afghanistan.

Those with loved ones who are veterans should remind them they're in a safe place and that they're not alone on the Fourth of July, Becerra suggested.

"Just be there and say, 'We're here,'" he said. "It will pass, and we'll be good to go."

Jake Messing, a social worker and behavioral health services program director for St. Catherine Hospital in East Chicago, offered similar advice.

"If you have a veteran that's a loved one or a neighbor, you may want to think twice about shooting off fireworks in their presence because that could be a very difficult thing for people," he said. "Most veterans tell me they don't like the Fourth of July."

When a person experiences trauma, especially a life or death situation, the brain remembers.

"It records in living Technicolor," Messing said.

Whatever was sensed in the moment - a sound, a smell - might trigger a flashback and a "danger" signal in the brain.

"The brain doesn't differentiate between something dangerous like bullets or a Fourth of July situation," Messing said. "The sight, the sound, the smell of any type of explosion turns on that super alert fight-or-flight."

Once the association is made, it can be tough to reverse. Medications don't help much, but some forms of therapy can be effective.

A downside to having a volunteer military is they tend to have multiple deployments, Messing said.

"Every time they go, they get exposed again to that stuff," he said. "One of the big problems is that veterans don't like to burden family members with what bothers them. We say, 'It's OK to let close loved ones know what bothers you. Otherwise they'll do it unintentionally, like with fireworks.'"

Becerra prefers watching professional displays these days.

"I try to make the best of it," he said. "To go to a function, knowing it's a controlled fireworks show, that's something I do sit through."